购买汽车最多的甲骨文展示客户

Question

我目前正在尝试回答以下问题：

显示从 Archie’s Luxury Motors 购买汽车最多的客户的姓名。

我正在使用的表：

客户

(custID, name, DOB, streetAddress, suburb, postcode,
gender, phoneNo, email, type)

销售交易

(VIN, custID, agentID, dateOfSale, agreedPrice)

我尝试了以下查询：

select customer.name
from customer, salestransaction
where customer.custid = salestransaction.custid
group by (salestransaction.custid)
having count(salestransaction.custid) = max(salestransaction.custid);

我收到以下错误：

ORA-00979: not a GROUP BY expression

请告诉我我做错了什么。

Answer 1

最简单的方法是使用 RANK：

select customer.name, st.cnt
from customer
join
 ( 
   select 
      custid,
      count(*) as cnt,
      rank() over (order by count(*) desc) as rnk
   from salestransaction
   group by custid
 ) st
on customer.custid = st.custid 
where st.rnk = 1;

Answer 2

这应该可行：

select * from (
select customer.name
from customer, salestransaction
where customer.custID = salestransaction.custID
group by (salestransaction.custID), customer.name
order by count(*) desc
) where rownum=1

Answer 3

select * from (
select customer.name, count(*)
from customer, salestransaction
where customer.custid = salestransaction.custid
group by (salestransaction.custid)
order by count(*) desc
) where rownum=1

Answer 4

使用连接而不是在 where 子句中加入它们，也将

SELECT c.name, MAX(s.custid) FROM (
SELECT c.name, Count(s.custid)
FROM customer c
INNER JOIN salestransaction s ON c.custid = s.custid
GROUP BY c.name);